How casually you view the work would of course impact your feelings about adaptations. The more seriously one takes a source work, the less comfortable one will be with people taking liberties with it. That is self evident.

Fandoms of legendaria and varied mythos can be quasi religious (see comic book guy, and all the con fanboys, including those in the movie fanboy, where Wars fanboys (and girls) actually desecrate Trek fanboy's statuary, resulting in an altercation) in their approach. And that, of course, comes in varying degrees. As a casually religious person will often not be bothered by the details of their religion, so long as people follow the spirit of it, whilst an orthodox person may become wroth you someone for transgressing on this or that holy edict, so to, the more casual approach to various legendaria is not all that concerned with faithful adherrence to the details of the mythos, while the more ardent approach can be sent into a cardiac episode by news of people quoting some altered detail from an adaptation as though it were legitimate cannon.

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Which is why don't really get what's there to "protect"

"Hear me, hounds of Sauron, Gandalf is here! Fly if you value your foul skins, I will shrivel you from tail to snout if you step within this circle!"

"Do not be to eager to deal out death in judgement. Even the very wise cannot see all ends."